The present invention relates to a hinge, particularly for rotatably coupling two components of a pair of eyeglasses preferably made of plastics.
Eyeglasses are currently known in which the temples, made for example of metal or acetate, are associated with the front, which is made of the same materials, by interposing a metallic hinge that is constituted by a first element, such as a perforated lug that is partially embedded in the front, and by a second element, constituted by two perforated shoulders that protrude from the tip of the temple; the first and the second elements are associated one another by a pivot.
The insertion of the pivot therefore allows to achieve both the positioning and the rotary coupling between the temple and the front.
However, these conventional hinges are not free from drawbacks: the pivot must have minimal tolerances to ensure the precise coupling between the temple and the front, and said tolerances, in view of the extremely small size of the pivot, require expensive precision machining operations; moreover, a certain time is required to assemble the hinge to the components of the eyeglasses, and this entails an increase in the production cost.
Another conventional solution entails, if the front and the temples are made of plastics, a direct coupling between the front and the temple of a pair of eyeglasses without using an interposed coupling hinge; said coupling is provided by means of two L-shaped flaps that are arranged in a mirror-symmetrical fashion with respect to a median plane lying longitudinally to said temple and protrude longitudinally and perimetrically from the tip of the temple.
Said two flaps can be arranged at two seats formed proximate to the lateral end of the front that can be arranged adjacent to the temple.
However, this conventional solution, too, has drawbacks: the center distance between the two seats formed on the front can be different from the one calculated for optimum coupling in relation to the center distance of the two flaps, thus entailing difficulty in coupling the temple to the front.
This requires the mutual positioning of the flaps and of the seats to be calculated with a certain precision: an excessive center distance could in fact lead to difficulty in mutually coupling the front and the temple, causing easy breakage of the two parts during assembly or during replacement of one of them, whereas an insufficient center distance would lead to easy disengagement between the temple and the front; the smaller the center distance, the easier this can be achieved.
Regardless of the above-mentioned drawbacks, the direct mutual coupling of the front and the temple, without using a hinge, occurs by elastic deformation of the end of the temples that is associable with the front; this entails that an excessive pressure applied at said end facilitates the breakage of the temples or of the flaps associated therewith during coupling to the front.
The difficulty in achieving optimum mutual pivoting of the temple and of the front in the above described solution is increased by the fact that the two seats for the two flaps must be formed on the front by using an insert in the mold provided with two undercuts.